The electronics industry uses flat flexible cables and circuits made up of copper foil conductors laminated between thin sheets of plastic insulating film. The foil may typically be of "one-two ounce copper" about 0.0027 inches thick, and the film about 0.001 to 0.004 inches. In manufacturing flat circuits, a layer of foil is bonded to one sheet of plastic film and then photo-etched to the desired pattern. A second sheet film is then bonded over the foil.
A problem exists in removing the film at those points where electrical connections are to be made, as by soldering. The film may be pre-punched with holes at the desired locations ("connection pads"), but there are known difficulties in getting accurate registration. Chemical removal of film has been practiced, but is slow. Heated-blade strippers are known but do not work well on high-temperature plastics such fluorocarbon or polyimide compounds. There hence exists a need for another method and means for local film removal which is rapid and does not leave any chemical or adherent residue.